Varnish

Varnish Cache is a web application accelerator also known as an HTTP accelerator. You can install it in front of any server that speaks the HTTP protocol and configure it to cache the contents. Varnish Cache is very, very fast and will improve your site's speed. One of the main attributes of Varnish Cache is the flexibility of its domain-specific language, VCL, which enables you to determine how incoming requests should be dealt with.

Memcached

Memcached is a general-purpose distributed memory caching system for boosting the loading speed of dynamic database-driven websites. It is used to decrease the number of times an external data source (such as a database or API) is read by caching data and objects in RAM. The Memcached distributed memory caching system uses a two-tier architecture. The Memcached distributed memory caching system is used by some of the most popular web sites on the web and is supported by popular Content Management Systems like Joomla and WordPress.

Node.js

Node.js is a software platform for writing scalable network apps. Written in JavaScript, Node.js uses an event-driven, asynchronous I/O model that makes it lightweight and efficient, suitable for real-time content-heavy Internet apps. Node.js uses Google's V8 JavaScript engine, libUV, and several built-in libraries.

InnoDB

InnoDB is the default storage engine for the MySQL open-source RDBMS. A storage engine is the main software component that a DBMS uses to create, retrieve, modify and delete data from a database. The latest version of InnoDB offers substantial improvements in efficiency, stability and functionality. InnoDB offers the standard ACID database transaction properties, along with declarative referential integrity support. InnoDB is included by default in most binaries distributed by MySQL AB.